从文件中读取字符串和原始数据类型并创建对象

Question

I'm reading from a file and using a scanner to read the inputs but am having difficulty understanding how to apply next() and nextLine() to assign data from the text to variables to be sent to my rectangle class constructor for printing these objects to the console. I get parsing the input (nextInt...etc.), but when strings and primitive data mix on the same line on multiple lines of a scanner read text file how do you handle this? Do I create multiple scanner loops for ints and String(s) to loop through it all to ensure the read data gets assigned to the array elements correctly?

TLDR: How do I read multiple strings and primitives from one .txt file, populate that data into my class fields to then create an array of objects and print *'s to the console to symbolize my created "rectangular" objects from said .txt file?

Answer 1

Check out this related question: Scanner is skipping nextLine() after using next(), nextInt() or other nextFoo() methods

I honestly didn't understand your explanation of the text input, but it might be because the Scanner#nextInt method does not consume the last newline ('\\n') character. If that's the case, a workaround is to call another nextLine() to consume it.

Also, Scanner#next do ignore whitespaces, but it doesn't ignore primitives, such as booleans or integers, as they are valid tokens.

Answer 2

When you get your string with nextLine() you have to split it with:

• something like String#substing(int begin, int end) more information
• or you use String#split(" ") and get a string array, which contains in index i the ith word. more information
• I think it is also possible to get your Data with nextInt() and your Reader will only give you the first piece of data. With another nextInt() the second number, and so on. But I'm not sure about this solution (But you can try it, through)

After that you can convert it to a datatyp you want to have. For example if you want a double you can use Double.parseDouble(stringVar) .

At Last you create your objects and you only have to find a way to print it.